Method, device and semi-finished product for producing prepared roofing for renewing rooves

ABSTRACT

The invention relates to a method for producing prepared roofing for renewing rooves, comprising a glass-nonwoven based planar structure ( 1 ) containing cavities ( 2, 3, 4, 5, 6, 7 ) spaced at intervals, which is laminated with a bitumen-based planar structure ( 10 ), a plastic film ( 8 ) being interposed between said structures. Said method is characterised in that the plastic film ( 8 ) is applied in a first step to a glass-nonwoven based planar structure ( 1 ) that has a mineral coating on one flat surface, by the application of molten plastic during an extrusion coating process to the opposite flat surface from the surface with the mineral coating. In a subsequent step, the bitumen-based planar structure ( 10 ) is laminated onto the surface of the glass-nonwoven based planar structure ( 1 ) that faces towards the applied plastic film ( 8) . This permits a cost-effective production. The invention also relates to appropriate embodiments of the method, to a device for carrying out the method and to a semi-finished product for producing the prepared roofing for renewing rooves.

[0001] The invention concerns a method and a semifinished product forproducing a renovation roof covering comprising vapor pressurecompensating devices, with a nonwoven glass cloth-based planar structurewhich is laminated on to a bitumen-based planar structure with theinterposition of a plastic film and which has openings arrangeddistributed at spacings and extending continuously from one flat side tothe other flat side.

[0002] It is known for existing roof covers to be renovated by arenovation roof covering being applied to the existing roof cover. Sucha renovation roof covering has a planar structure based on nonwovenglass cloth, of which a flat side is connected to a bitumen-based planarstructure, with the interposition of a plastic film. The planarstructure based on nonwoven glass cloth has openings which extendcontinuously from one flat side to the other. The operation of fittingthe renovation roof covering is effected in such a way that it is laidon the roof cover, with its flat side which is remote from thebitumen-based planar structure. Then, heat is applied from the flat sideof the renovation roof covering, which has the bitumen-based planarstructure, for example by means of a torch, more specifically in such away that the renovation roof covering is caused to adhere or is meltedto the existing roof cover. Due to the effect of heat, the bitumen-basedplanar structure becomes partially liquid. The plastic film which coversover the openings in the nonwoven glass cloth-based planar structuremelts away in that procedure so that the bitumen can penetrate throughthe openings and can become firmly joined to the surface of the roofcover to be renovated. The join is effected only in the region of theopenings and thus partially and not over the full area involved, in sucha way that vapor pressure equalisation is made possible in that manner.The openings in the nonwoven glass cloth-based planar structure arestamped out at regular intervals prior to final production and forexample measure approximately 2.5 cm×7 cm.

[0003] It is known, for the production of a renovation roof covering ofthe above-indicated kind, to use a laminating installation or amanufacturing installation of another kind, wherein a nonwoven glasscloth-based planar structure having the openings, a plastic film and abitumen-based planar structure are introduced into the installationsimultaneously or in succession, and are joined to each other. It hasbeen found that handling and introducing a thin plastic film in alaminating installation or manufacturing installations of another kindcause problems and often result in operational difficulties anddisturbances.

[0004] The object of the invention is essentially that of making theknown method of producing a renovation roof covering of the kind setforth in the opening part of this specification, more rational thanhitherto.

[0005] In accordance with the invention, to attain that object, it isprovided that a mineral coating is applied to the one flat side of thenonwoven glass cloth-based planar structure and the plastic film isapplied to the other flat side of the nonwoven glass cloth-based planarstructure provided with openings, by the application of plastic materialin the molten condition in an extrusion coating process, and that thebitumen-based planar structure is laminated on to the side of thenonwoven glass cloth-based planar structure, that is towards the appliedplastic film.

[0006] Application of the plastic film by applying plastic material inthe molten condition is more rational and less expensive thanintroducing a plastic film into a laminating installation or amanufacturing installation of another kind, for the production ofrenovation roof coverings.

[0007] In regard to the openings provided in the nonwoven glasscloth-based planar structure, it can further be provided in accordancewith the invention that, during the operation of applying the plasticfilm by applying plastic material in a molten condition in an extrusioncoating process to the planar structure provided with openings, thepressing pressure applied to the side opposite to the side at which theplastic material is applied is of such a value that no plastic materialapplied is pressed through the openings.

[0008] In a further embodiment of the invention it can be provided thata polyethylene layer of a weight in relation to surface area in therange of between 15 g/m² and 50 g/m² is applied as the plastic film tothe planar structure provided with openings. The density of thepolyethylene applied in the extrusion process is preferably in the rangeof between 0.915 g/cm³ and 0.960 g/cm³.

[0009] In a further embodiment of the invention it can be provided thatthe plastic film to be applied in the molten condition in the extrusioncoating process is applied to project beyond at least one side edge ofthe nonwoven glass cloth-based planar structure, in such a way that inthat fashion the plastic film is caused to project beyond the edge ofthe nonwoven glass cloth-based planar structure. Such a projectingportion affords advantages in regard to the laying procedure by virtueof additional reliable overlap of the individual strips of roofcovering.

[0010] As conventional extrusion coating installations are only designedfor coating carrier materials of full surface area, in a furtherconfiguration, in regard to the openings provided in the nonwoven glasscloth-based planar structure, it is provided that the pressing roller ofa laminating device used in the extrusion coating process has a nonstickcoating.

[0011] In an advantageous embodiment of this feature it can be providedthat the pressing roller is in the form of a rubber roller covered witha polytetrafluoroethylene-based tube. Alternatively it can be providedthat the pressing roller is in the form of a rubber roller over which isglued a polytetrafluoroethylene-based band.

[0012] A further embodiment of the invention provides that the nonwovenglass cloth-based planar structure has on its flat side remote from theplastic film a nonstick application which is in the form of a mineralcoating.

[0013] The invention further concerns a semifinished product forproducing a renovation roof covering for renovating existing roof coversor the like comprising a first material web portion which forms thesemifinished product and which has a nonwoven glass cloth-based planarstructure with openings which are arranged distributed at spacings andwhich extend from one flat side to the other, to the one flat side ofwhich, to provide a renovation roof covering, a second material webportion in the form of a bitumen-based planar structure is fixedlyconnected, with the interposition of a plastic film. In accordance withthe invention it is provided that the plastic film is fixedly applied ona flat side of the nonwoven glass cloth-based planar structure, morespecifically preferably in that plastic material has been applied in amolten condition in an extrusion coating process to a flat side of thenonwoven glass cloth, wherein the openings in the nonwoven glasscloth-based planar structure are covered over by the applied plasticfilm. In a further configuration of the invention the flat side oppositeto the flat side with the applied plastic film has a nonstickapplication in the form of a mineral coating.

[0014] The invention is described in greater detail by way of examplehereinafter with reference to the drawings in which:

[0015]FIG. 1 is a diagrammatic plan view of an embodiment of asemifinished product according to the invention for the production of arenovation roof covering,

[0016]FIG. 2 shows a sectional view taken along section line II-II inFIG. 1 on an enlarged scale, and

[0017]FIG. 3 is a diagrammatic sectional view through a renovation roofcovering which is applied to an existing roof cover but which has notyet been glued or melted to the existing roof cover.

[0018]FIG. 1 shows a plan view of a semifinished product in accordancewith the invention. A nonwoven glass cloth-based planar structure 1 hasopenings 2, 3, 4, 5, 6, 7 which are arranged distributed at spacings andwhich are continuous from one flat side to the other through the planarstructure. One of the two flat sides is fixedly joined to a plastic film8 which also covers over the openings 2 through 7. The flat side of thenonwoven glass cloth-based planar structure 1, which is opposite to theplastic film 8, has a mineral coating 9. The plastic film 8 has beenapplied to the planar structure 1 provided with openings, by theapplication of plastic material in a molten condition in an extrusioncoating process, more specifically in such a way that the openings 5through 7 are also covered over by the plastic film 8.

[0019] The article shown in FIG. 1 or FIG. 2 is a semifinished product.To produce a renovation roof covering, a bitumen-based planar structure10 is applied to the plastic film 8. That affords a renovation roofcovering which is generally identified by reference 11 and which, forrenovating an existing roof cover 12 (FIG. 3), is applied to the surface13 thereof, with the flat side having the mineral coating 9. The fixingof the renovation roof covering 11 on the surface 13 is effected bywarmth or heat being supplied (for example by a torch) to the renovationroof covering 11, from its surface identified by 14. That warmth or heatdestroys the plastic film 8 in the region of the opening 5, and hot andliquid bitumen which issues from the bitumen-based planar structure 10penetrates through the opening 5 (and naturally also through the otheropenings) so that the renovation roof covering is caused to adhere or isfused firmly to the surface 13 of the roof cover 12 to be renovated, inthe region of the openings.

[0020] The thickness dimensions of the individual components shown inFIGS. 2 and 3 relative to each other are only selected to make thedrawing clear and do not correspond to the actual conditions involved.

1. A method of producing a renovation roof covering (11) with vaporpressure compensating devices, comprising a nonwoven glass cloth-basedplanar structure (1) which is laminated on to a bitumen-based planarstructure (11) with the interposition of a plastic film (8) and whichhas openings (2, 3, 4, 5, 6, 7) which are arranged distributed atspacings and extending from one flat side to the other, characterised inthat a mineral coating (9) is applied to the one flat side of thenonwoven glass cloth-based planar structure (1) and the plastic film (8)is applied to the other flat side of the nonwoven glass cloth-basedplanar structure (1) provided with openings, by the application ofplastic material in the molten condition in an extrusion coatingprocess, and that the bitumen-based planar structure (10) is laminatedon to the side of the nonwoven glass cloth-based planar structure (1),that is towards the applied plastic film (8).
 2. A method as set forthin claim 1 characterised in that during application of the plastic film(8) by applying plastic material in the molten condition in theextrusion coating process to the planar structure (1) provided withopenings the pressing pressure applied to the side opposite to the sideat which the plastic material is applied is of such a value that noapplied plastic material is pressed through the openings (2, 3, 4, 5, 6,7).
 3. A method as set forth in claim 1 or claim 2 characterised in thatthe plastic film which is to be applied in the molten condition in theextrusion coating process is applied projecting beyond the planarstructure (1) at one longitudinal side or at both longitudinal sides(preferably about 15 cm).
 4. A method as set forth in one of claims 1through 3 characterised in that a polyethylene layer of a weight inrelation to surface area approximately in the range between 15 g/m² and50 g/m² is applied to the planar structure provided with openings.
 5. Amethod as set forth in one of claims 1 through 4 characterised in thatthe density of the polyethylene applied in the extrusion process isapproximately in the range of between 0.915 g/cm³ and 0.960 g/cm³.
 6. Adevice for carrying out the method as set forth in one of claims 1through 5 characterised in that the pressing roller of a laminatingapparatus used in the extrusion coating process has a nonstick coating.7. A device as set forth in claim 6 characterised in that the pressingroller is in the form of a rubber roller covered over with apolytetrafluoroethylene-based tube.
 8. A device as set forth in claim 6characterised in that the pressing roller is in the form of a rubberroller with a polytetrafluoroethylene-based band glued thereover.
 9. Asemifinished product for producing a renovation roof covering (11) forrenovating existing roof covers (12) or the like, preferably for use ina method as set forth in one of claims 1 through 5, comprising a firstmaterial web portion which forms the semifinished product and which hasa nonwoven glass cloth-based planar structure (1) with openings (2, 3,4, 5, 6, 7) which are arranged distributed at spacings and which extendthrough the planar structure (1) from one flat side thereof to theother, to the one flat side of which, for providing the renovation roofcovering, a second material web portion in the form of a bitumen-basedplanar structure (10) is fixedly joined, with the interposition of aplastic film (8), characterised in that the plastic film (8) is fixedlyapplied to a flat side of the nonwoven glass cloth-based planarstructure (1), preferably by applying plastic material in the moltencondition in an extrusion coating process.
 10. A semifinished product asset forth in claim 9 characterised in that the flat side opposite to theflat side of the planar structure (1) with plastic film (8) appliedthereto has a mineral coating.
 11. A semifinished product as set forthin claim 9 or claim 10 characterised in that the plastic film (8)projects beyond at least one side edge of the nonwoven glass cloth-basedplanar structure (1).